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COB PCB Assembly
COB PCB Assembly refers to a "chip-level board-level packaging" technology where bare chips (Dies) are directly mounted on a PCB, with electrical connections achieved through gold wire/aluminum wire bonding, and encapsulated using epoxy resin or silicone.
- Maximum panel size 54 inches
- Maximum panel thickness 0.450 inches
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Our COB PCB Assembly Service Capabilities
Zintilon Technology is committed to providing advanced COB PCB assembly services to global users, supporting COB PCB assembly from prototype production in the product R&D stage to small-batch manufacturing. From printing to assembly, we ensure to deliver efficient and reliable COB PCB assembly solutions for you.
COB PCB Assembly Materials
| Category | Recommended Model/Specification | Key Parameters | Remarks |
|---|---|---|---|
| Bare Die Bonding | ① Conductive Silver Adhesive (EP3-EP17); ② Insulating Epoxy Adhesive (EP138) | Curing condition: 120–150°C for 30 minutes; Thermal conductivity: 2–5 W/m·K; Shear strength: ≥ 15 MPa | Silver adhesive is used for power chips, while insulating adhesive is used for signal chips |
| Bonding Wire | ① Gold Wire (25 µm, Au 99.99%); ② Aluminum Wire (30 µm, Al 99%) | Tensile strength: ≥ 6 g for gold wire, ≥ 4 g for aluminum wire; Arc height: 0.10–0.25 mm | Gold wire is used for high-reliability applications, and aluminum wire for cost-sensitive scenarios |
| Substrate PCB | ① High Tg FR-4 (Shengyi SY-1140); ② Metal Core PCB (MCPCB, 6061 Aluminum) | Tg ≥ 170°C; CTE: 13–15 ppm; MCPCB thermal conductivity: 1–3 W/m·K | Aluminum substrates are preferred for LED COB, and FR-4 for signal COB |
| Encapsulation Adhesive | ① High-Transmittance Silicone (OE-6650); ② Low-Stress Epoxy (EP-121) | Light transmittance: ≥ 90%; Hardness: 60–95 Shore D; CTE: 26 ppm | Outdoor applications require UV resistance (no yellowing after 1000 hours of UV exposure) |
| Thermal Interface Material (TIM) | Silicone Pad or Thermal Grease (2–5 W/m·K) | Thickness: 0.1–0.2 mm; Dielectric strength: ≥ 3 kV | Used between the module and heat sink |
COB PCB Assembly Surface Finishes
| Process | Thickness | Advantages in COB | Limitations |
|---|---|---|---|
| ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) | Ni 3–5 µm + Pd 0.05 µm + Au 0.03 µm | Compatible with both gold wire and aluminum wire bonding; resistant to black nickel; wire bonding strength ≥ 6 g | Highest cost |
| ENIG (Electroless Nickel Immersion Gold) | Ni 3–5 µm + Au 0.05 µm | Suitable for conventional gold wire bonding; flatness < 0.3 µm | Plasma cleaning required for aluminum wire bonding |
| Immersion Silver (ImAg) | 0.15–0.3 µm | Ideal for high-frequency signal COB; low skin effect loss | Requires vacuum packaging; storage life: 6 months |
| OSP (Organic Solderability Preservative) | 0.2 µm | Ultra-low RF loss; suitable for non-heating areas of LEDs | Not resistant to multiple high-temperature cycles; limited to one-time encapsulation |
Why Choose Our
COB PCB Assembly Service?
One-on-One Quotation
Simply upload your .gbr file to receive a quotation feedback within 24 hours. Our professional engineers will analyze your design to avoid misunderstandings, communicate with you, and provide a reasonable price.
High-Quality Assembled
We maintain a rigorous and responsible attitude toward materials, processes, surface treatments, A.O.I (Automated Optical Inspection), and flying probe testing, ensuring consistent high quality from prototype production to mass manufacturing.
Fast Delivery
Equipped with advanced machinery and a professional quotation team to ensure fast delivery. We prioritize orders based on requirements and complexity.
Real-Time Communication
For your benefit, we provide full-cycle technical support for each customer from quotation to delivery. We will respond quickly to any questions until you confirm satisfactory COB PCB assembly.
COB PCB Assembly Standards
Zintilon ensures quality through our cob PCB assembly design and manufacturing standards from design to delivery by follow up IPC standards (IPC-2221C, IPC-6012E) to ensure manufacturability and reliability.
Parameter
Wire-bond (glue)
Flip-chip (bump)
Note
Placement accuracy
Value/Requirement ±10 µm @ 3σ
Source/Remarks ±5 µm @ 3σ
Cpk ≥1.33
Adhesive/bump height
Value/Requirement 20–50 µm (Ag-epoxy)
Source/Remarks 50–80 µm bump
Voids <10 % area
Cure profile
Value/Requirement 120–150 °C / 30–60 min
Source/Remarks Vacuum 5 mbar / 10 s
Shear ≥15 MPa
COB PCB Assembly Guidelines
Ensure precise tolerances, select appropriate materials, maintain clear CAD designs, and follow toolpath optimization for best results. Zintilon delivers accuracy, quality, and consistency in every COB PCB assembly.
Item
Value/Requirement
Source/Remarks
Chip Bonding Area Size
Value/Requirement Bare die periphery + 0.2–0.4 mm
Source/Remarks Ensures adhesive overflow and prevents air bubbles
Conductive Adhesive Layer Thickness
Value/Requirement 20–50 µm (for silver adhesive)
Source/Remarks Thermal conductivity: 2–5 W/m·K; air bubble area < 10%
Bonding Pad
Value/Requirement NSMD (Non-Solder-Mask-Defined) opening; copper pad ≥ 100 µm × 100 µm; pitch ≥ 75 µm
Source/Remarks Compatible with 25 µm gold wire
Bonding Wire Arc Height
Value/Requirement 0.10–0.25 mm (low loop)
Source/Remarks Encapsulation adhesive thickness ≥ 0.5 mm for full coverage
Encapsulation Adhesive Thickness
Value/Requirement 0.5–1.5 mm (depending on chip height)
Source/Remarks Hardness: 60–95 Shore D; CTE: 26 ppm
Curing Parameters
Value/Requirement Silicone: 150°C for 60 minutes; Epoxy: 120°C for 30 minutes
Source/Remarks Curing degree ≥ 95%; no volatile voids
Tensile Test
Value/Requirement Gold wire ≥ 6 g; Aluminum wire ≥ 4 g; Shear strength ≥ 15 MPa
Source/Remarks JEDEC JESD22-B116
Thermal Cycling
Value/Requirement -40 ↔ +125°C for 500 cycles; wire tensile strength reduction ≤ 20%
Source/Remarks IPC-A-610 G Class 3
UV Resistance
Value/Requirement Outdoor adhesive: 1000 hours @ 85°C/UV-A 340 nm; ΔYI < 3
Source/Remarks No yellowing; light transmittance retention ≥ 90%
Our COB PCB Assembly Service for Various Industrial Applications
COB PCB Assembly (Chip On Board PCB Assembly) leverages four core advantages: "ultra-high integration, minimal interconnection path, excellent optical adaptability, and low-cost miniaturization". It has become the "compact performance core" for precision electronic devices, covering key application scenarios from micro-sensing to display terminals.
COB PCB Assembly FAQs
We cooperate with multiple certification bodies and can handle CE certification, FCC certification, RoHS certification, FDA certification, etc.
We have a highly professional engineering team with extensive design experience in fields such as industrial control, consumer electronics, new energy, and medical devices.
Throughout the product development process, we confirm each step with the client. If the project design includes sample testing, we will conduct electrical performance testing, functional testing, performance testing, and reliability testing to ensure design quality.
Got any more questions?
Ultimate Guide
to COB PCB Assembly
to COB PCB Assembly
COB PCB Assembly Service
Various and Robust COB PCB Assembly Services
Prototype
Prototyping
From Gerber files to circuit boards, our professional engineering team provides you with the highest quality rigid PCB manufacturing services. We meticulously control every detail of the process, including drilling, electroplating, and AOI, ensuring precise control over trace spacing, thickness, and panel dimensions. We are committed to providing you with the most reliable PCB assembly.
- Complete production line
- Professional engineering support
- 10+ years‘ manufacturing experience
Production
Production
We have our own production lines and a robust manufacturing network. From PCB design, engineering, and manufacturing, we have sufficient capacity to provide you with professional and fast delivery services, whether for small or large batches. We spare no effort in providing consistent mass production services for your products.
- Strong supply chain team
- Competitive pricing
- One-stop service from design to delivery
Let’s Build Something Great, Together
